Automatic playing attachment for pianos



A. JOHNSON, A. C. SWANSON AND A. HIUTTERBERG.

AUTOMATIC PLAYING ATTACHMENT FOR PIANOS.

Patented June 17, 1919.

' APPLICATION HL'ED'JUNEZL 1916.

2 SHEETS-SHEET I.

mrzRls PETERS cm, PrtoIu-Ll 1N0 WASHING mm o. 4:v

A. JOHNSON,A. C. SWA'NSON AND A. H. UTTERBERG AUTOMATIC PLAYING ATTACHMENT FOR P IANOS. APPLICATIQN FILED JUNE 21. 1916.

1,307,052. Patented June 17, 1919.

2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

ALFRED JOHNSON, ARTHUR C. SWANSON, AND ALFRED H. UTTERBERG, OF CHICAGO, ILLINOIS.

AUTOMATIC PLAYING ATTACHMENT FOR PIANOS.

Specification of Letters Patent.

Patented June 17, 1919.

Application filed June 21, 1916. Serial No. 104,850.

ing attachments for pianos and particularly to detalls of simplified construction and arrangement for increasing the efliciency with reduced cost of manufacture.

One of the features of our invention 1s simplified construction for the pneumatic key actuating structures, the construction involving a minimum number of simple parts easily assembled or taken apart. Another feature of the invention resides in simplified and more practical connection between the pneumatics and the striker rods which enables the rods to be readily applied and disconnected and which yieldingly and noiselessly holds the rods in place during playing. Another feature of the invention resides in an improved vacuum chest in the form of a continuous one-piece board routed out and apertured to form vacuum compartments and connections thereof with the pneumatic key actuating structures. Another feature of the invention resides in the simplified arrangement for supporting the pneumatic key actuating structures on the vacuum chest and connectingthem with the vacuum compartments and ducts leading to the tracker board hose connections. The

arrangement is such that by loosening one screw a set of pneumatlc key actuating structures are released and can readily be withdrawn.

The above enumerated features and others are embodied in the structure shown on the accompanying drawings, in which drawings Figure 1 is a plan view with parts broken away to more clearly reveal theconstruction and arrangement, I

Fig. 2 is a front elevational View of part of the structure,

Fig. 3 is a sectional view on plane 3-3, Fig. 1,

Fig. 4 is a sectional view on plane 1-4, Fig. 3, and

Fig. 5 is a sectional view on plane 5-5, Fig. 3.

The vacuum chest 10 is a continuous onepiece board routed out to form the main vacuum compartment 11 and the sets of passageways 12 and 13 for extending the vacuum compartment to the ports or openings for communicating with the pneumatic key actuating structures- The board is secured to two end blocks 11 and 15 extending at right angles therefrom by means of which the vacuum chest can be secured in a piano frame. Through the end block 11 is the passageway 16 which communicates with the exterior and with the hole 17 in the chest leading to the vacuum compartment thereof. As best shown in Fig. 1, an annular slot 18 is cut into the end block 11 around the outer end of passageway 16 to leave the annular flange 19. Into this slot is inserted the end of a flexible conductor 20 preferably of rubber which intimately receives the flange 19 to make an air-tight connection, this conductor in practice leading to the main suction bellows.

In Fig. 3 the construction of the pneumatic key actuating structures P is shown. Each structure comprises the rectangular valve box 21 having the forward extension 22. A plate 28 is hinged at its rear end to the bottom of the valve box at the rear et thereof and fabric 24 is secured thereto and to the box to form the well known bellows or pneumatic. The box 21 has the annular slot or passageway 25 around the platform 26, the space 27 being above the diaphragm 28 which is secured at its periphery to the outer rim'of the platform, the platform being hollowed out to provide the atmosphere space 29 below the diaphragm and the central pocket 30. Surrounding the upper end of the space 27 is the depressed annular seat 31 for a metal valve seat disk 32, a sealing washer 33 being preferably applied between the disk and seat. This disk hasthe opening 31 concentric with the diaphragm, and for controlling said opening a valve disk 35 is provided. This disk is at its lower surface faced by leather 36 and its top faced with leather 37. The valve disk has the axial hole 38 therethrough for receiving a screw 39, the upper part of the hole being countersunk to receive the correspondingly shaped head of the screw. The threaded end of the screw is secured in a block 40 of substantially three-sided crosssection with the sides concave, as shown in Fig. 1, the opening 34 being sutficiently large to allow the block to project upwardly therethrough. Between the valve disk and the block yielding washers 41 are inserted and the screw fits loosely in the hole through the valve disk so that the disk and block may readily tilt relatively. "Secured centrally and on the upper face of the diaphragm 28 is a-plate 42 for engaging'with the-lower end of the valve block in order that the valve block and the valve will be raised when the diaphragm is raised. Then the diaphragm is-down'the valve rests on'the seating disk 32 and closes the opening 34'leading to the space 2 7 above the diaphragm.

The top of the box 21 is formed by a cover 43 which is detachably secured by means of screws-44, the lower end of the cover being preferably faced by leather 45. Concentric with the valve 35thecover has'the cylindrica-lvalve chamber 46 from which a passageway 47 extends rearwardly and connects with the port 48 extending downwardly through the box 21 and communicating with the interior of the bellows. Above the valve chamber 46 is the port 49, this port being normally open but being closed by the valve 35 when this valve is raised the diaphragm to open theport 34, the=bellows being normally connected with atmosphere through the passageways 48 and 47 and the port 49.

In the front end of the bio-x 21 is the longitudinal duct-5O leading to the annular slot and the space 27. Extending through this duct and radially through the platform 26 to the pocket 30 belowthe diaphragm-is a tube 51,*the tube extending ashort distance outside of the duct 50. In the outer'end of the duct 50 is secured the annular plug 01'-- bushing 52. I

Through the front'wall 53 of the vacuum chest 10 are the circular openings 54 for re.-

. 'ceiving the projecting-ends ofthe bushings 52, this "connection effecting communication betweenthe vacuum compartments in the vacuum chest andtlie'spaces withinthe valve boxes above the diaphragms. To more thoroughly seal the connection between the chest and valve boxes the rear ends of the valve boxes are faced by leather 55. In the rear wall 56 of the vacuum chest vertical channels 57 are bored in alinenient with the openings 54 in the front wall, and secured in the rear wall'are tubes 58, these tubes communicating with the channels 57 and extending through and a distance beyond the'openings 54 to telescopically receive the 7 outer ends of the tubes 51 extending from the valve boxes. To seal the joints between the tubes rubber sleeves 59 are secured at their inner ends to the tubes 51 and at their outer ends receive the tubes 58, as clearly shown'in Fig. 3.

On top of the vacuum chest a cover 60 is detachably secured by screws 61 and this cover has the channels 62 extending up wardly from its lower face and then forwardly therethrough with nipples 63 inserted in the front ends. The inner ends of the channels register with the various channels 57, and at intermediate pointthimbles 64 are inserted in the cover to connect the channels through small bleed openings 65 withthe vacuum compartment 11. To seal the connection between the cover and chest leather 66 is preferably provided. Hose lengths 67 connected with the nipples 63 lead to thetracker board 68 to communicate with the tracker board openings 69 over which the music sheet 7 0 travels in practice.

Normally the diaphragm 01" each pneumatic key actuating structure is down and the valve 35 opens the bellows to atmosphere through port 49 and disconnects the bellows from the space above the die. phragm, there being vacuum above the diaphragm by virtue of duct50 and also vacuum below the diaphragm by virtue of bleed opening 65, the channels 57 and the tubes 58 and 51. As a music sheet travels along the tracker board its openings come into register with the tracker boa-rd openings and then through the channels 62 and 57 and the tubes 58 and 51 atmosphere is admitted into the space below the diaphragm and the diaphragm is thrown upwardly to'shift the valve 35 to close the atmosphere inlet 49 to the bellows and to connect the bellows with the vacuum compartment in the vacuum chest,

and the bellows plate23 is drawn upwardly. On account of the triangular cross-section of the valve block 40 the air can readily flow through the'port 34 when the block extends therethrough. As soon as the tracker board opening is again closed the suction becomes etfectiveat the lower sideof the diaphragm through the bleed opening 65 and the diaphragm is quickly pulleddownwardly to disconnect the bellows from vacuum and reconnect it with atmosphere and the bellows plate will thendrop.

' The pneumatic key actuating structures are secured to thevalv'e chest in three rows, the structures ofeach row half-way overlapping those of the row below. The bellows of each row are'also separated a distance'to provide space for clamping rods 71 which are secured to the vacuum chestand extend rearwardly'therefrom. Each'rod tends at its end through the center of the cross plate 72 and threadedly receives a nut 3. Each cross plate engages against the rear ends of adjacent valve boxes 21, the rear ends of the boxes having preferably the grooves 74 for receiving and confining the plates. lVith this arrangement the pneumatic key actuating structures are readily accessible from the rear of the piano, and by inserting a screw driver between the structures the nuts 73 can readily be reached and turned to release the plates 72 or to secure them against the structures.

As shown in the drawings the vacuum chest is placed in front of the piano action upright rods with the bellows extending rearwardly. Secured to and projecting rearwardly from each bellows plate 23 is a shelf 75 having a slot 7 6 cut longitudinally therein from its outer end. Secured to the shelf above and below the inner end of the slot are the upper and lower leather disks 77 and 78 provided with the holes 79 and 80 from which entrance slits 81 and 82 respectively extend radially rearwardly in line with the arm slot 76, the holes in the washers being concentric with the semi-circular inner end of the slot. At the end of the extension 2'2 of each valve box a guide bracket 83 is provided having the guide passageway Sat therethrough for the striker rod 85, the striker rod having the head 86 for engaging with the under side of a head 87 adjustably secured by means of a threaded stem 88 in the extension 89 extending from the upright rod 90 0f the piano action. At its lower end each rod has a screw 91 secured axially therein a distance, the projecting shank of the screw passing through the holes 79 and 80 of the disks 7'7 and '78 and through the slot 76 of the bellows arm 75. The holes Set in the brackets 83 are preferably lined with the yielding material 92 such as felt or leather, and the lower ends of the heads 86 are preferably provided with a facing 93 of leather or felt. The openings 84 are also preferably of larger diameter than the rods 85 so that the rods can be swung laterally a considerable distance. With this arrangement a rod can readily be removed from its connection with the bellows bottom by pulling on its lower end to draw the screw 91 throughthe slits 81 and 82 of theleather disks. Likewise, a rod can be readily reconnected by pushing the screw inwardly through the slits, and after such insertion the slits close themselves and yieldingly lock the rod to the bellows. The projecting endof the screw is preferably of a length to cause the bottom of the rod and the head of the screw to always abut against the upper and lower disks respectively. On account of the soft leather disks this will produce a yielding and flexible connection but one which has no lost motion and which is therefore noiseless. Instead of providing a single bracket 83 on each valve box, a continuous bracket may extend full length of the valve box rows and be secured here and there to the boxes of the top row. Shorter lengths of bracket could also be used to guide the striker rods of a number of pneumatic key actuating structures.

When pneumatic key actuating structures are to be removed for inspection or repairs the corresponding striker rods are 'disconnected and raised out of the way and then when the corresponding nut 73 i withdrawn and the clamping plate 74 released, the structures can be pulled away from the vacuum chest. \Vhen a structure is to be replaced its tube 51 is inserted into the corresponding tube 58 and the rubber sleeve 59 is engaged over the tube 58 and the bushing 52 is inserted in the corresponding opening 54, and then when the clamping plate 7i is applied and the nut 7 3 screwed onto the corresponding rod 71, the pneumatic key actuating structure will be forced against the back of the vacuum chest and accurate connection is established. After securing of the key actuating structures the corresponding striker rods are lowered and re-connected at their lower ends with the bellows bottom. The striker rods could, of course, engage with the piano action at different places. As shown in the drawin s, the rods engage with the abutments on the vertical rods of the piano action but the player attachment could be positioned within the piano casing to bring the striker rods below the rear ends of the keys.

e thus produce a pneumatic playing attachment which comprises a minimum of parts and is therefore of very simple and inexpensive construction. This reduction in parts also increases the playing efiiciency. The single piece vacuum chest body is a decided improvement over prior art constructions in which the vacuum chest is construct-- ed of numerous parts. Furthermore, by ha ing the vacuum chest body of a. single piece it is of greater strength and afi'ords better and more rigid support for the pneumatic key actuating structures and keeps the striker rods at all times in perfect alinement with the piano action members to be engaged. The simple construction of the pneumatic key actuating structures with the number of parts reduced to a minimum increases their efliciency, they being very quick to respond and there being no lost motion.

We do not, of course, desire to be limited to the exact construction and arrangement herein shown and described as changes and modifications are no doubt possible which would still come within the scope of the invention.

Ve claim as follows:

1. In pneumatic playing mechanism for pianos, the combination of a vacuum chest having a vacuum compartment, valve boxes, openings in said chest communicating with the vacuum compartment, vacuum ducts in said valve boxes, sleeves for holding said ducts in alinement with said openings, said chest having atmosphere channels, said valve boxes having atmosphere spaces, and conabove the dia )hra m o )enin 's 'to the vacub 7 it:

um compartment of said vacuum chest, bushings for alining said openings with said valve box ducts, said chest having atmosphere channels, tubes extending from said channels through said openings, and tubes extending from the spaces below the diaphragms for telescoping into said first-mentioned tubes.

3. In pneumatic playing mechanism for pianos, the combination of a'vacuum' chest having a'vacuum compartment, valve boxes secured with their ends against a face of said chest, a valve and an actuating diaphragm therefor in each valve box, there being space above and below said diaphragm, a duct in each valve box communicating with the space above the diaphragm, openings to the vacuum compartment of said vacuum chest, bushings for alining said openings with said valve box ducts, said chest having atmosphere channels, tubesv extending from said channels through said openings, tubes extending from the spaces below the 'diaphragms for telescoping into said first-men tioned tubes, and afiexible sealing sleeve surrounding the junctures of said tubes.

tjIn pneumatic playing mechanism :for pianos, the combination of a vacumn chest having a vacuum compartment, a valvesbox' secured with its end against a. face of said chest, a vacuum duct leading from theend of said box to the interior of said box, a bushing extending from said vacuum duct, said vacu- Gopies of this patent may be obtainedfor five-cents each,-byaddressing the Commissioner 'of Patents,

scopically receiving the atmosphere tube of said box.

5. In neumatic la m mechanism for a 0 l h p1anos,the combination of avacuum chest havnw a vacuum com a-rtment and an o eningleading therefrom, saidchest having an' atmosphere channel, a tube leading :from said atmosphere channel in line with said opening, a. valve box having a vacuum duct terminating at its end for communicating with said opening, and a tube extending from-saidboxithrough said vacuum for communicating with said atmosphere tube in the i chest.

6. In pneumatic playing mechanism for V p1anos,:the combination of a vacuum chest having a vacuum compartment and an opening therefrom, an atmosphere channel in said chest and a tube extending therefrom into said opening,.a valve box having a vacuum duct and an atmosphere inlet, and means for seculingsaid box to said chest with its vacuum duct and atmosphereinletin communication respectively with said opening and said tube.

7. In pneumatic playing mechanism for pianos, the combination of a vacuum chest having a vacuum compartment and an opening therefrom and having an atmosphere.

having a vacuum ductand an. atmosphere chamber, a tube extendchannel, a valve box ing from said valve box atmosphere chamher through the valve box-vacuumI duct, and means for'securing said box to saidchest with the vacuum fduct of the box in communication with the vacuum chest opening and with saidtube in communication with the atmosphere chamber;

:In witness whereof we hereunto subscribe ourna-mes this 17th day- 7 f June, A. D. 1916.

ALFRED JOHNSON. ARTHUR C. SWAN SON. .ALFRED 1-H. UTTERBERG.

:Washington, D. 0. 

